An object or act that assures one of safety and security.
This phrase was first derived from the blanket a characket from Peanuts(Charlie brown) always had with him. If memory serves me right a US Present coined the phrase.
1. The addition of cameras and patrolling officers will creat a security blanket for the students on campus.
2. Driving fast makes me feel safe. Like wrapping a blanket around me, it shields all the bad things from coming in.